British Foreign Secretary Philip Hammond, left, President Obama, British Prime Minister David Cameron and NATO Secretary-General Anders Fogh Rasmussen attend a meeting on Afghanistan on the first day of the NATO 2014 summit on Sept. 4 at the Celtic Manor Resort in Newport, Wales. Saul Loeb, AFP/Getty Images

French President Francois Hollande, left, Ukrainian President Petro Poroshenko, President Obama, British Prime Minister David Cameron, German Chancellor Angela Merkel and Italian Prime Minister Matteo Renzi hold a meeting on the situation in Ukraine at the Celtic Manor Resort during the 2014 NATO Summit in Newport, Wales. Saul Loeb, AFP/Getty Images

British Prime Minister DavidCameron and President Obama meet schoolchildren at Mount Pleasant Primary School before the NATO summit on Sept. 4 in Newport, Wales. Leaders and senior ministers from 60 countries are meeting at what has been billed as the most important NATO summit since the end of the Cold War with the situation in Ukraine and the threat of the Islamic State likely to be top of the agenda. Pool photo by Tim Ireland